Light-Emitting Diodes (LEDs) and Organic Light-Emitting Diodes (OLEDs) have been used in making color display panels. As with an LCD display, an OLED display produces color images based on three primary colors in R, G and B. A color pixel in an OLED display can be made of an R sub-pixel, a G sub-pixel and a B sub-pixel. In general, the response of the OLED material over current is approximately linear and, therefore, different colors and shades can be achieved by controlling the currents. The advantage of OLEDs over Liquid-Crystal Display (LCD) includes the fact that OLEDs are able to emit light whereas a pixel in an LCD acts as a light-valve mainly to transmit light provided by a backlight unit. Thus, an LED/OLED panel can, in general, be made thinner than an LCD panel. Furthermore, it is known that the liquid crystal molecules in an LCD panel have slower response time and an OLED display also offers higher viewing angles, a higher contrast ratio and higher electrical power efficiency than its LCD counterpart.
A typical LCD panel has a plurality of pixels arranged in a two-dimensional array, driven by a data driver and a gate driver. As shown in FIG. 1, the LCD pixels 5 in a LCD panel 1 are arranged in rows and columns in a display area 40. A data driver 20 is used to provide data signals to each of the columns and a gate driver 30 is used to provide a gate line signal to each of the rows. In a color display panel, an image is generally presented in three colors: red (R), green (G) and blue (B). Each of the pixels 5 is typically divided into three color sub-pixels: red sub-pixel, green sub-pixel and blue sub-pixel. In some color display panels, each of the pixels 5 also has a white (W) sub-pixel. Whether a pixel has three sub-pixels in RGB or four sub-pixels in RGBW, the data provided to each pixel has only three data signals in RGB.